Improvement in the manufacture op ultramarine



HENRY A1 LUD'WIG, on NEW YORK, N. Y.

) Letters Patent No. 97,941, datedbecember 14, 1869.

MM IMPROVEMENT mane MANUFACTURE OP ULTRAMARINE.

The Schedule referred to in these Letters Patent and making part of the same.

1'0 a lljwhont it may concern.-

Be it known that I, HENRY A. LUDWIG, of the city, county, and State of New York, have invented a new and useful ln'iprovementin the Manufacture of Ultra-marine, 0t which the following is a full, clear,

and exact description.

My invention consists in a certain mixture or combination' of ingredients for the manufacture of artificialultramarine,whereby an article having a finer color is produced. Theproportion of the several ingredients may be more or less varied, as may also the periods of their exposure to heat and the temperature of the ovens in whichthe mass is treated; also, other ingredients, ifnecessary, be added,but the ingredients hereinafter named, mixed in or about the proportions described,and treated substantially as specified, I

know, from actual experiment, will suffice. As in the treatment of other compounds for the production of ultramarine, I first subject the mass to a high temperature, in one. oven, and afterward to a lower temperature, in another oven, for the purpose of desulphurizing it, and prefer to use for suchpnrpose, a furnace in which both ovens, that areal-ranged one above the other, are heated by the same fire, and

which furnace ismade the subject of a separate application for 'Lcttcrs Patent.

, 'lhus, discarding the use of sulphate of soda, as

generally used in such mixtures, I take, say, eighty to one hundred pounds (80 to 100 lbs.) of carbonate a of soda, ninety to one hundred pounds (90 to 100 lbs.) ofburnt clay, sixty to one hundred pounds (60 to 100 lbs.) of sulphur, six pounds ((ilbs.) of charcoal, three to fourpounds (3 to 4 lbs.) of colophony or rosin, thirty to forty pounds (30 to 40 lbs.) of silicate of potassa orsoda, or ofbotln'commonlyknown as soluble glass, or, in place of this latter ingredient, forty-five pounds (45 lbs.) of silica.

To mix and treat these several ingredients, I take, first, the 'soda, clay, sulphur, charcoal and rosin, and finely grind the same, and afterward mix them with j the soluble glass or silica, and put the mass into the ordinary'or any suitable crucibles. :These crucibles are then covered up and placed in the lower or hotter ovenof the two ovenshereinbefore referred to, thefire gradually increasing in temperature, until, after from ten to fourteen hours, the mass has been brought to a red heat. After the mass has been in said oven from sixteen to cighteemhours, altogether, this part of the process is completed, and the oven allowed to cool down, and the fused mass taken out andcrushed. The

mass is thenintroduced into the upper or cooler oven, and which need only be hot enough to effect desulphurization. It. may be placed in iron vessels within this oven, or be spread over the bottom of the same, and may remain 'in said oven while a fresh charge is being treated in the first oven, so that where the two ovens are combined in the one furnace, the latter need not he opened to interfere with the process going on in the first oven. Upon the mass or color being taken out of the second oven, it is washed, to remove the soda. This may be done in any suitable manner, but

I prefer the effect the same by throwing the color into a hogshead fitted with a perforated false bottom, over which coarse linen cloth, previously soaked. in water,

is spread. The color being put into said hogshead so as to nearly fill it, hot boiling water is poured in until it completely covers the color, which is allowed to remain in soak for about six hours, when the water is drawn off, by means of a faucet near the bottom of the hogshead. Such washing of the color maybe repeated twice, after ivhich it is ground and sifted to separate the different grades or qualities, and subsequently dried or roasted in iron pans, and ground again, when it is ready for the market. I

' Having thus described my improvementin the manufacture of ultramarine,

I claim as new-'-- The combination of ingredients, herein named, mixed and treated substantiallv as specified.

HENRY A. LUDWIG.

Witnesses F. HAYNES, HENRY PALMER. 

